JP7714940B2 - Medical Sheets - Google Patents

Description

The present invention relates to a medical sheet, and more specifically to a medical sheet that is placed in the surgical field and used for various measurements, etc.

Microsurgery, which uses a surgical microscope to dissect and suture minute tissues such as blood vessels and nerves, is widely performed on various organs.

In microsurgery, needles with a diameter of about 50 μm to 100 μm and threads with a diameter of about 10 μm to 20 μm are used. Both the needles and threads are very fine, and require extremely precise work.
Furthermore, when suturing tissues, it is sometimes required to match the dimensions of the two tissues to be sutured, and it is important to accurately grasp the dimensions of the tissues at the surgical site.

Patent Document 1 describes a graduated adhesive tape for medical use as a measuring component for medical applications.

Japanese Patent Application Publication No. 8-56983

The graduated adhesive tape described in Patent Document 1 is intended to record the progress of treatment with photographs and is used by being attached to the affected area, i.e., it is not intended to be used on internal organs.
Furthermore, in microsurgery, it is not possible to attach graduated adhesive tape to the tissue to be treated, and therefore the graduated adhesive tape described in Patent Document 1 cannot be applied.

In addition, if the temperature of tissue rises due to the effects of lighting during surgery, there is a risk that cells may be damaged or die due to protein denaturation, so there is also a need to easily determine the temperature conditions within the surgical field.

In light of the above circumstances, the present invention aims to provide a medical sheet that can contribute to accurate measurement of tissue during microsurgery and makes it easy to grasp temperature changes at the site where it is placed.

One aspect of the present invention is a medical sheet comprising a sheet-like main body and an image area having a plurality of lines formed on the main body.
At least one of the body and the image portion contains a temperature-responsive material that changes color at a predetermined temperature.
The pitch of the lines is 500 μm or less, and the width of the lines is 100 μm or less.
In this medical sheet, the image area is formed by printing ink containing a temperature-responsive material onto the main body.

The medical sheet of the present invention can contribute to accurate measurement of tissue during microsurgery and makes it easier to monitor temperature changes at the site where it is placed.

1 is a plan view of a medical sheet according to a first embodiment of the present invention. 10 is a diagram showing an example of a state in which the color of an image portion has changed in the medical sheet. FIG. FIG. 4 is a plan view of a medical sheet according to a second embodiment of the present invention. 10 is a diagram showing an example of the medical sheet in which the color of the main body has changed. FIG. FIG. 10 is a plan view of a medical sheet according to a modified example of the present invention.

A first embodiment of the present invention will be described below with reference to FIGS. 1 and 2. FIG.
1 is a plan view of a medical sheet 1 according to this embodiment. The medical sheet 1 comprises a sheet-like main body 10 and an image area 20 formed on the main body 10.

The main body 10 is made of a biocompatible material, specifically, examples of biocompatible materials include polymers such as silicone, polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), polyester, polyvinyl chloride (PVC), polymethyl methacrylate, polyether ether ketone (PEEK), polyethersulfone (PES), polysulfone (PSU), polyphenylsulfone (PPSU), polyacetal (POM), polyphenylsulfide (PPS), polyetherimide (PEI), polyimide (PI), polylactic acid, polyglycolic acid, polycaprolactone, polycarbonate, polyethylene, and polypropylene, copolymers of these polymers, metals and oxides thereof such as titanium alloys, stainless steel, and cobalt alloys, thermosetting elastomers such as silicone rubber, urethane rubber, fluororubber, natural rubber, and synthetic rubber, and thermoplastic elastomers such as polystyrene-based (TPS), polyolefin-based (TPO), urethane-based (TPU), and polyester-based (TPEE). The polymer binder described above may also contain an inorganic powder. The inorganic powder may be silica, alumina, zinc oxide, or titanium oxide. The inorganic powder content may be 5% to 70% by weight. An inorganic pigment may also be contained.
The main body 10 may be in the form of either a film or a plate. Furthermore, it may be either flexible or rigid, and can be appropriately selected taking into consideration the target organ, procedure, etc.

The main body 10 only needs to be opaque, specifically, have a transmittance of 1% or less. If the biological tissue in contact with the surface of the main body 10 opposite to the surface on which the image area 20 is formed is not visible through the main body 10, the tissue can be accurately confirmed during microsurgery.
The color of the main body 10 is preferably a complementary color of the biological tissue. These complementary colors can be blue, greenish blue, blue-green, bluish green, green, yellowish green, and yellow-green, ranging from blue to yellow-green. These colors ranging from blue to yellow-green correspond to B, BG, G, and GY on the Munsell color scale. By making the color of the main body 10 a color ranging from blue to yellow-green, the biological tissue becomes easier to see. Specifically, the ranges of L*, a, and b in the L*ab color space of the main body 10 are preferably 25 to 80, -80 to 0, and -50 to 50, respectively.

For the main body 10, it is preferable that the spectral reflectance from 570 nm to 800 nm of visible light (wavelength band approximately 350 nm to 800 nm) be 20% or less. If the main body is made of the metal mentioned above, the above colors can be achieved by printing paint all over the surface. A low brightness for the main body 10 is preferable, as it provides good contrast with biological tissue. The peak reflectance of visible light for a main body with such brightness is generally 10% or less.

There are no particular restrictions on the thickness of the main body 10, but it can be between 15 μm and 2 mm. For highly elastic materials, it can be approximately 0.1 mm to 1.0 mm, for low-elasticity materials, it can be approximately 0.02 mm to 0.2 mm, and for metals, it can be approximately 0.01 mm to 0.1 mm.

The planar shape of the main body 10 exemplified in this embodiment is a rounded rectangle, but the planar shape is not limited to this and can be triangular, circular, or other suitable shape. It is preferable that the planar shape of the main body 10 be a polygon with rounded corners. This shape is less likely to damage tissue and is easier to grasp with tweezers or a manipulator. The polygon can also be a convex hull. A convex hull is less likely to get caught on tissue.

The image area 20 is formed on the main body 10 by printing.
The image area 20 is made up of a plurality of lines. While Fig. 1 shows an example in which a plurality of orthogonal lines are arranged to form a grid, the arrangement of the lines in the image area 20 is not limited to this and can be set appropriately depending on the object to be measured, etc. Examples include a ruled line arrangement consisting of only a plurality of parallel lines, a concentric circle arrangement, a radial arrangement, etc.

The line width in the image area 20 is 100 μm or less, and the distance (pitch) between adjacent lines is 500 μm or less. Within this range, the image area 20 may include two or more types of lines with different widths, or may have multiple areas with different pitches (distance between lines). Image areas with such dimensions are difficult to see with the naked eye, but can be easily seen when viewed with a magnifying glass during microsurgery.

The ink for forming the image area 20 contains a temperature-responsive material whose color changes depending on the temperature, and a binder.
Examples of temperature-responsive materials include inorganic compounds such as mercury iodide and dimethylammonium compounds, liquid crystals such as cholesterol derivatives and cyanobiphenyls, and organic compounds such as leuco dyes, spirooxazines, salicylideneanilines, bianthrones, and polydiacetylenes, which undergo reversible or unidirectional color changes due to changes in the intermolecular forces, transitions, dehydration reactions, stereochemistry, or molecular structure of the respective substances.
The temperature-responsive material may be used as it is, or may be mixed into the ink in a state where it is encapsulated in microcapsules or the like.

It is preferable that one of the colors of the temperature-responsive material before and after the change is easily visible on the main body 10, that is, that the color is complementary to the color of the main body 10. A material that is transparent either before or after the change can also be used as the temperature-responsive material in this embodiment.
The temperature-responsive material preferably changes color at a temperature in the range of 30° C. to 80° C., and more preferably at a temperature in the range of 40° C. to 50° C. If the temperature at which the color changes is close to the temperature at which tissue is damaged, an unfavorable condition at the surgical site can be detected early, and appropriate measures can be taken to reduce damage to the tissue.

A single type of temperature-responsive material may be used, or two or more types may be mixed together.

To adjust the color of the lines, pigments that do not change color with temperature may be mixed into the ink.
As the pigment, either an organic pigment or an inorganic pigment can be used.
Examples of inorganic pigments that can be used include oxides, hydroxides, sulfides, selenides, and ferrocyanides of metals such as titanium, zinc, gold, silver, copper, and iron, as well as chromates, sulfates, carbonates, silicates, and phosphates of these metals. Other examples include the above-mentioned metals themselves or their alloys, carbon, and pearl pigments such as bismuth oxychloride, titanium mica, and fish scale foil. Among these, biocompatible materials such as titanium dioxide (titania), zinc oxide, talc, silica, mica, alumina, barium sulfate, calcium carbonate, magnesium carbonate, barium silicate, calcium silicate, metal soap, and silicone are preferred.
Examples of organic pigments include nitroso-based, nitro-based, azo-based, lake-based, phthalocyanine-based, condensed polycyclic materials, and other carbon compounds.

A resin can be used as a binder. The resin can be a composition, and the composition can be a mixture of oligomers and polymers. The resin can be soluble. The resin can be a curable resin. The curable resin can be an ionizing radiation curable resin or a thermosetting resin. The ionizing radiation curable resin can be an ultraviolet curable resin or an electron beam curable resin. The type of resin can be an acrylic resin, a urethane resin, an epoxy resin, a polyester resin, a thiol resin, or a mixture of these. As the acrylic resin, a fluorine-based acrylic resin, a silicone-based acrylic resin, an epoxy acrylate resin, an acrylonitrile styrene resin, or a mixture of these can be used. Other resins that can be used include methylstyrene resin, fluorene resin, polypropylene, PET (polyethylene terephthalate), PC (polycarbonate), PS (polystyrene), COC (cyclic olefin copolymer), COP (cycloolefin polymer), MS (methacrylate-styrene copolymer), AS (acrylonitrile-styrene copolymer), PEN (polyethylene naphthalate), PI (polyimide), phenolic resin, melamine resin, epoxy resin, alkyd, etc.

In addition to the above, engineering plastics such as PBT (polybutylene terephthalate), POM (polyoxymethyl), PA (polyamide), and PPS (polyphenylsulfide), as well as super engineering plastics, can also be used as binders.

It is preferable to use either aqueous ink or non-aqueous ink for forming the image area 20 depending on the surface characteristics of the main body 10. If the surface of the main body 10 is hydrophilic, it is preferable to use aqueous ink. If the surface of the main body 10 is hydrophobic, it is preferable to use non-aqueous ink.
Various solvents can be used to adjust the solids content and viscosity of the ink. For example, water (purified water) or alcohol can be used for aqueous inks. For non-aqueous inks, high-boiling solvents that do not evaporate easily at room temperature (aliphatic hydrocarbons, glycol ethers, higher alcohols, etc.) and low-boiling solvents that evaporate easily at room temperature (MEK, ethanol, acetone, etc.) can be used alone or in combination. Other solvents that can be used include dodecane, tetradecane, and toluene.

The ink may contain organic or inorganic fine particles. Specific examples include acrylic particles, styrene particles, styrene-acrylic particles and crosslinked bodies thereof, particles of melamine-formalin condensates, polyurethane particles, polyester particles, silicone particles, fluorine-containing particles, epoxy particles, copolymers thereof, clay compound particles such as smectite, kaolinite, and talc, inorganic oxide particles such as silica, titanium oxide, alumina, silica-alumina, zirconia, zinc oxide, barium oxide, and strontium oxide, calcium carbonate, barium carbonate, magnesium carbonate, barium chloride, barium sulfate, barium nitrate, barium hydroxide, aluminum hydroxide, strontium carbonate, strontium chloride, strontium sulfate, strontium nitrate, strontium hydroxide, and glass particles.
These particles can be used alone or in appropriate combinations. Furthermore, they may be surface-treated by coating, vapor deposition, or the like before use.

There are no particular limitations on the printing method for forming the image area 20. Examples of printing methods include offset printing, gravure printing, flexographic printing, screen printing, gravure offset printing, reverse offset printing, screen offset printing, pad printing, and inkjet printing.
Among these, gravure offset printing and screen offset printing are particularly suitable because they can stably form narrow lines.

The ink used to form the image area 20 is preferably made of a biocompatible material. After forming the image area 20 with ink that is not made of a biocompatible material, the biocompatibility of the medical sheet 1 can also be ensured by covering the ink area with a transparent, biocompatible coating. In this case, the coating may cover only the image area 20, or may cover the entire surface of the main body 10.
The coating material may be a biocompatible material that can be used for the ink that forms the main body 10 and the image area 20. Preferred examples include silicone resin and fluororesin.

The operation of the medical sheet 1 configured as above when in use will now be described.
The medical sheet 1 is placed at the surgical site where the treatment will be performed, either as is or cut to an appropriate size. By placing the organ or tissue to be treated at an appropriate position on the medical sheet 1 or slightly above the medical sheet 1, the dimensions of the organ or tissue can be determined based on the image area 20.

When the temperature of the image area 20 rises due to factors such as heat from the lighting illuminating the surgical field, and reaches a temperature that causes a temperature change, the color of the image area 20 changes. This allows the user to intuitively and easily recognize the temperature of the area where the medical sheet 1 is placed, and by taking appropriate measures and procedures as necessary, damage to the tissue being treated, its surrounding tissue, or the graft can be effectively prevented. If the color change of the temperature-responsive material is reversible, it is easy to know when the temperature-lowering procedure has been successful.

The color change can be set in a wide variety of ways depending on the temperature-responsive material contained in the image area 20. Some examples are given below.
The image area 20 changes color and brightness while maintaining visibility relative to the main body 10.
2, the image area 20 may be made less visible by changing its color to the same color as the main body 10 or by becoming transparent. In this case, the user may become aware of temperature changes because it becomes difficult to grasp the dimensions of the organs and tissues.
In either of the above embodiments, the user can intuitively and easily recognize the temperature change.

If the color change temperature of the image area 20 is slightly lower than the temperature at which tissue is damaged, it is easier to prevent damage by recognizing the temperature change before the tissue is damaged. If the color change temperature of the image area 20 is the same as or slightly higher than the temperature at which tissue is damaged, it is easier to minimize damage to tissue by responding quickly after recognizing the color change.

In this embodiment, it is preferable for the image area 20 and the main body 10 to have a brightness difference of at least a certain level, as this will result in good contrast. For example, a difference in average reflectance (%) of visible light of approximately 30 points will result in good contrast. Alternatively, the contrast between the image area 20 and the main body 10 can be a color density difference of 0.1 or more and 2.0 or less, and to further improve visibility, a difference of 0.5 or more and 1.5 or less is preferable.

The height of the image area 20 (the thickness of the layer formed on the main body 10) is preferably 1 μm or more and 10 μm or less for ease of visibility. Examples of the cross-sectional shape of the image area 20 include semicircular, semi-elliptical, triangular, trapezoidal, rectangular, and trapezoidal or rectangular shapes with a convex curved upper portion. If the corners of the cross-sectional shape have edges, blood and cleaning fluid are more likely to remain on the image area 20 due to surface tension. However, rounded corners of the cross-sectional shape are preferred because they make it less likely for blood and cleaning fluid to remain on the image area 20. Furthermore, semicircular, semi-elliptical, triangular, and trapezoidal shapes are preferred because they make it less likely for blood and cleaning fluid to remain on the image area 20 and allow it to flow easily from the medical sheet, making it easier to maintain the visibility of the image area 20 during microsurgery.
The height of the image area 20 can be easily adjusted by printing ink on the main body 10 in overlapping fashion at the same location.

A second embodiment of the present invention will be described with reference to Figure 3. In the following description, components that are common to those already described will be assigned the same reference numerals and duplicate descriptions will be omitted.

3 is a plan view of a medical sheet 101 according to this embodiment. The medical sheet 101 includes a main body 110 and an image area 120 provided on the main body 110.
The image area 120 of this embodiment does not contain a temperature-responsive material, and therefore does not change color with temperature. Instead, the main body 110 is formed to contain a temperature-responsive material. In other words, the medical sheet 101 according to this embodiment is configured so that the color of the main body 110 changes with temperature.

The method for incorporating the temperature-responsive material into the main body 110 can be selected as appropriate. If the main body 110 is made of synthetic resin, elastomer, or the like, the temperature-responsive material can be incorporated by mixing and kneading the base material. If the main body 110 is in the form of a hard sheet, the temperature-responsive material can be incorporated by forming a colored layer containing the temperature-responsive material on the surface of the main body.

The procedure for using the medical sheet 101 and the effects it provides are generally similar to those of the first embodiment. When the temperature of the main body 110 rises due to heat from lighting or other factors and reaches a temperature that causes a temperature change, the color of the main body 110 changes. This allows the user to intuitively and easily recognize the temperature of the area where the medical sheet 101 is placed.
4 shows a medical sheet 101 in which the color of the main body 110 has changed. In FIG. 4, the color of the main body 110 has become closer to the color of the image area 120, thereby reducing the visibility of the image area 120.

The medical sheet according to the present invention will be further described using examples. The present invention is not limited in any way to the specific content of the following examples.

Example 1
Example 1 is an example according to the second embodiment.
A green temperature-responsive material was mixed with a two-component curing silicone resin and cast into a 0.1 mm thick green body. The temperature-responsive material is derived from a leuco dye, and becomes transparent at temperatures above 40°C.

A grid-like image area with a pitch of 100 μm was printed on the main body. The basic line width was 20 μm, and for the purpose of using it as a measurement guide, every fifth line was wider, at 30 μm. The ink used to form the image area was a white ink made of silicone resin with 40 wt% titanium oxide added as a pigment, and did not contain a temperature-responsive material.
After printing, the ink was heated and cured at 140°C for 10 minutes to obtain the medical sheet of Example 1. When the line width of the printed area was measured, it increased by about 2% compared to before heating, but did not change by more than 10%, so there was no problem with the dimensional accuracy of the scale.

When the medical sheet of Example 1 was observed using a binocular microscope at a magnification of 40 times, the contrast between the printed area and the main body was good, and the printed area was clearly visible.
When a pig's blood vessel was placed on a medical sheet and observed under a binocular microscope, the dimensions such as length and diameter could be easily determined based on the imaged area.

When the medical sheet was immersed in saline and heated, the main body turned a cloudy white color due to the silicone resin when the temperature of the saline reached 45°C. This significantly changed the appearance of the medical sheet, clearly reducing the visibility of the printed areas, making it easy to tell when the temperature had reached 40°C or higher.

Example 2
Example 2 is an example according to the first embodiment.
The main body was a green silicone resin sheet (thickness: 0.3 mm) that did not contain any temperature-responsive material.
A grid-like image area with a pitch of 500 μm was printed on the main body. The basic line width was 40 μm, and for the purpose of using it as a measurement guide, every fifth line was made wider, 50 μm.
The ink used to form the image is a blue ink made of silicone resin with 50 wt% of a temperature-responsive material added. The temperature-responsive material used is a white material made of microencapsulated cholesteryl derivatives. This temperature-responsive material changes color above 50°C, becoming colorless.
After printing, the ink was heated and cured at 140°C for 5 minutes to obtain a medical sheet according to Example 2. When the line width of the printed area was measured, it increased by about 2% compared to before heating, but did not change by more than 10%, so there was no problem with the dimensional accuracy of the scale.

When the medical sheet of Example 2 was observed using a binocular microscope at a magnification of 40 times, the contrast between the printed area and the main body was good, and the printed area was clearly visible.
When a pig's blood vessel was placed on a medical sheet and observed under a binocular microscope, the dimensions such as length and diameter could be easily determined based on the imaged area.

When the medical sheet was immersed in saline and heated, the printed area became colorless when the temperature of the saline reached 60°C. This resulted in a significant change in the appearance of the medical sheet, with the visibility of the printed area clearly decreasing, making it easy to tell when the temperature had reached 60°C or higher.

Each embodiment of the present invention has been described in detail above with reference to the drawings, but the specific configuration is not limited to this embodiment, and configuration changes and combinations may be made without departing from the spirit of the present invention. Some examples of changes are given below, but these are not all inclusive and other changes are also possible. Two or more of these changes may be combined as appropriate.

- In the medical sheet according to the present invention, only a portion of the image area may contain a temperature-responsive material. In the modified medical sheet 1A shown in Figure 5, only the temperature display area 21 formed within a portion of the grid of the image area 20A contains a temperature-responsive material, and changes color at a predetermined temperature. In this way, it is possible to easily grasp changes in temperature without changing the visibility of the multiple lines in the image area 20A. If the color of the temperature display area 21 before the change is transparent, the temperature display area becomes visible only when the predetermined temperature is reached, making it easy to take measurements up to that point.

In the above-described examples, there is an area without lines on the peripheral edge of the main body in a plan view, but this is not essential, and lines may be provided over the entire surface of the main body.
Small pieces may be provided protruding from the periphery of the main body to make it easier to grip with forceps or the like.
The visible light reflectance of the main body may have multiple peaks. Even in this case, as long as at least one peak is present in the wavelength range of 450 nm to 570 nm, the contrast with biological tissue will be good and visibility will be excellent.

- Even if the ink that forms the lines and information areas is biocompatible, a coating may be applied. During use, saline or other liquid is continuously sprayed on the medical sheet to prevent it from drying out, and a coating can prevent the saline or other liquid from attacking the lines and information areas.

- In the medical sheet according to the present invention, an information section indicating the line width or pitch value may be provided on the main body. If the pitch is small, for example, part of the image area may be omitted where the information section is provided. It is also possible to configure the sheet so that only the information section contains a temperature-responsive material, as in the modified example described above.

- The total thickness of the medical sheet, including the main body and the image area, can be, for example, 0.02 mm or more and 1.0 mm or less. By making it 0.02 mm or more, transportability during manufacturing is maintained and the dimensional accuracy of the image area is also easily ensured. By making it 1.0 mm or less, flexibility is easily achieved, making it easy to use in microsurgery.

The image area does not necessarily have to be formed directly on the main body. For example, the image area may be formed on the main body by bonding a sheet on which the image area has been formed to the main body using an adhesive, heat fusion, thermocompression, or the like.
Examples of adhesives that can be used include vinyl acetate, acrylic, urethane, rubber, and silicone adhesives. In order to maintain sufficient bonding under the expected usage environment, the storage modulus of the adhesive is preferably 1.0E+04 Pa or more at 100°C.
The adhesive may be pre-processed into a sheet, or may be applied directly to the body. The bonding surface of the body may be subjected to a surface treatment such as corona treatment to increase the bonding strength.

- Both the main body and the image area may contain a temperature-responsive material.

1, 1A, 101 Medical sheet 10, 110 Main body 20, 20A, 120 Printing area

Claims (4)

A sheet-like main body,
an image area formed on the main body and having a plurality of lines;
Equipped with
At least one of the main body and the image area contains a temperature-responsive material that changes color at a predetermined temperature;
the color change of the temperature-responsive material is reversible;
The pitch of the plurality of lines is 500 μm or less,
The width of the lines is 100 μm or less.
Medical sheets. A sheet-like main body,
an image area formed on the main body and having a plurality of lines;
Equipped with
At least one of the main body and the image area contains a temperature-responsive material that changes color at a predetermined temperature;
The pitch of the plurality of lines is 500 μm or less,
The width of the lines is 100 μm or less,
the image area is formed by printing ink containing the temperature responsive material on the body;
Medical sheets. The body is flexible.
The medical sheet according to claim 1 or 2 . Further comprising a coating covering the image area.
The medical sheet according to claim 1 or 2 .